Crimpable electrical terminal

ABSTRACT

An electrical terminal is adapted for use with an electrical conductor. The terminal has a terminating portion with a generally U-shaped cross-section having a web and a pair of sidewalls extending from two opposite longitudinal edges of the web. The sidewalls are generally trapezoidally shaped with relatively wide bases, joined to the longitudinal edges of the web, and relatively narrow tips. The bases are transversely aligned across the web. The tips are offset across the web so that the tips are spaced longitudinally of the web. Therefore, the tips will bypass each other when crimped toward each other to terminate the electrical conductor, all within the longitudinal confines of the bases of the sidewalls.

FIELD OF THE INVENTION

This invention generally relates to the art of electrical connectorsand, particularly, to a crimpable electrical terminal for terminating anelectrical conductor, such as a flat flexible circuitry.

BACKGROUND OF THE INVENTION

Electrical terminals are used in a wide variety of applications forterminating electrical conductors so that the conductors can beconnected to other electrical devices. The terminals often have contactportions whereby the terminated conductors are connected to the otherelectrical devices through interengagement of the contact portions ofmating terminals.

With the ever-increasing miniaturization of contemporary electronics andelectrical devices, it continuously becomes increasingly difficult todesign electrical terminals which meet the dimensional parameters orsize restrictions required in many applications. In other words, theelectrical terminals have become smaller and smaller, resulting in manydesign difficulties.

For example, cellular or mobile telephones have become increasinglysmaller in size or overall dimensions. Correspondingly, the batterypacks for such telephones are a fraction of the size of battery packsonly a few years ago. These battery packs require electrical terminalswhich, in turn, also must be considerably miniaturized. Suchminiaturization creates all kinds of problems in terminal configurationand design. For instance, heretofore, the terminals in a battery packfor a cellular or mobile telephone most often were soldered to theconductors of flat flexible cables within the pack. Because of theminiaturization, such soldering techniques have become increasinglydifficult, if at all possible since the high temperature for solderingcould destroy the conductor on the flat flexible circuitry.Consequently, crimp terminals have been considered for such uses.

Heretofore, crimp terminals most often have included a channel-shapedterminating portion for receiving the electrical conductor to beterminated. The channel-shaped terminating portion includes a base orweb, with a pair of sidewalls extending from the two oppositelongitudinal edges of the web. The sidewalls are crimped inwardly towardeach other for terminating the electrical conductor. If the sidewallsare disposed diametrically opposite each other, i.e. transversely acrossthe web, obviously the web and, in turn, the terminating portion of theterminal must be sufficiently wide to allow the sidewalls to be fullybent inwardly toward the opposite sidewalls. In order to reduce thewidth of the terminating crimp portion of the terminal, the crimpablesidewalls have been staggered lengthwise of the terminal so that thesidewalls can be crimped in a fashion to bypass each other when crimpedgenerally toward each other. However, when the sidewalls are staggeredto reduce the width of the terminal, the length of the terminal then ismade longer than if the sidewalls were diametrically opposite eachother. This dilemma has caused considerable comprises in reducing theoverall dimensions of such crimpable terminals.

The present invention is directed to solving the above problems in acrimpable electrical terminal which has reduced dimensional parametersthan heretofore has been available in the prior art.

SUMMARY OF THE INVENTION

An object, therefore, of the invention is to provide a new and improvedcrimpable electrical terminal of the character described, forterminating an electrical conductor.

In the exemplary embodiment of the invention, the electrical terminalincludes a contact portion at one end and a terminating portion at anopposite end. The contact portion and the terminating portion form anelongated unitary structure, such as of stamped and formed sheet metalmaterial. The terminating portion is generally U-shaped in cross-sectionand includes a web and a pair of sidewalls extending from two oppositelongitudinal edges of the web. The sidewalls have a general trapezoidshape with relatively wide bases, joined to the longitudinal edges ofthe web, and relatively narrow tips. The bases are transversely alignedacross the web. The tips are offset across the web such that the tipsare spaced longitudinally of the web. Therefore, the tips will bypasseach other when crimped toward each other to terminate the electricalconductor, all within the longitudinal confines of the bases of thesidewalls.

The electrical terminal is shown herein adapted for use with a flatflexible circuit. The terminal also includes a contact portion which isgenerally channel-shaped in cross-section generally transverse to theterminating portion.

Other objects, features and advantages of the invention will be apparentfrom the following detailed description taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of this invention which are believed to be novel are setforth with particularity in the appended claims. The invention, togetherwith its objects and the advantages thereof, may be best understood byreference to the following description taken in conjunction with theaccompanying drawings, in which:

FIG. 1 is a perspective view of a portion of a battery pack housing ontowhich a pair of the electrical terminals according to the invention havebeen mounted;

FIG. 2 is a perspective view of one of the terminals mounted to aplastic wall of the battery pack housing;

FIG. 3 is a side elevational view looking toward the left-hand side ofFIG. 2;

FIG. 4 is a fragmented vertical section similar to the elevational viewof FIG. 3, but with the sidewalls of the terminal crimped about the flatflexible circuit;

FIG. 5 is a perspective view of the stamped terminal attached to itscarrier;

FIG. 6 is a perspective view of the battery pack housing withoutterminals;

FIG. 7 is a perspective view of the battery pack with terminals prior tobeing crimped to the flat flexible circuit;

FIG. 8 is a fragmented perspective view of an anvil and a punch forcrimping the terminal of FIGS. 1-4;

FIG. 9 is a fragmented side elevational view of one of the terminalspositioned between the anvil and the punch;

FIG. 10 is an end elevational view somewhat schematically showing theterminal between the anvil and the punch;

FIG. 11 is an elevation view of the terminal attached to the dielectricmaterial and the flat flexible cable and

FIG. 12 has a top view of the terminal of FIG. 11.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in greater detail, and first to FIG. 1, theinvention is embodied in a crimpable electrical terminal, generallydesignated 10, which is shown mounted to a wall 12 (FIG. 2) of a frame,generally designated 14 (FIG. 1), of a battery pack for a cellular ormobile telephone. The entire battery pack is not shown in the drawings,but frame 14 is sufficient for a clear and concise understanding of theinvention as embodied in terminal 10. Two of the terminals are shownmounted to frame 14 in FIG. 1. Generally, each terminal 10 is adaptedfor terminating to a flat flexible circuit 16 shown in phantom.

The term "flat flexible circuit" is used herein in a generic sense toinclude conductors in conventional flexible flat cables and flexiblecircuitry of the type produced by etching or otherwise. Conductors ofthese types include flat conductors encased in an insulating film suchas Mylar (polyethyleneterephthalate). Of course, it should be understoodthat the concepts of the invention herein for considerably reducing thedimensions of a crimpable electrical terminal are equally applicable foruse with a wide variety of electrical conductors.

Referring to FIG. 3 in conjunction with FIGS. 1 and 2, each crimpableelectrical terminal 10 includes a contact portion, generally designated20, at one end of the terminal, and a terminating portion, generallydesignated 22, at the opposite end of the terminal. Contact portion 20and terminating portion 22 form an elongated unitary structure which canbe fabricated of stamped and formed sheet metal material. The contactand terminating portions generally define a longitudinal axis 24 of theterminal.

Contact portion 20 is generally channel-shaped in cross-sectiongenerally transverse to terminating portion 22 and longitudinal axis 24as seen best in FIGS. 2 and 3. The channel-shaped portion includes abase 26 and a pair of legs 28. Base 26 is generally flat (actually,slightly curved) to form a contact surface 30 which is engageable with acomplementary contact within the telephone (not shown). Legs 28 areadapted for bending and clamping about wall 12 of frame 14. The legs areshown in phantom in FIG. 3 projecting rearwardly of base 26 in astraight configuration to allow the terminal to be mounted onto thefront of wall 12. When so mounted, the legs are bent toward each otheras shown in full lines in FIG. 3 to embrace wall 12 and securely mountthe terminal to frame 14.

Terminating portion 22 of terminal 10 is generally U-shaped incross-section and includes a web 32 an elongated dimple 33, and a pairof side walls extending from the two opposite longitudinal edges of theweb. The side walls are generally trapezoidally shaped with relativelywide base portions 34a, joined to the longitudinal edges of web 32, andrelatively narrow tips 34b which have beveled edges. It can be seenquite clearly in FIG. 3 that bases 34a of sidewalls 34 are transverselyaligned across web 32, i.e. transversely of longitudinal axis 24. Thisenables the terminating portion of the terminal to have as short adimension as possible, i.e. in contrast to longitudinally offsetting thebases of the sidewalls. On the other hand, tips 34b of sidewalls 34 areoffset transversely of web 32 (i.e. longitudinally of axis 24) such thatthe tips are spaced longitudinally of the web. Therefore, the tips willbypass each other when crimped toward each other to terminate electricalconductor 16. This allows for the terminating portion of the terminal tobe as narrow as possible.

FIG. 4 shows sidewalls 34 of one of the terminals 10 crimped onto flatconductor cable 16. Arrows "A" indicate the crimped "height" of theterminating portion 22 of the terminal. FIG. 4 also shows that a contactplating 36 can be applied to surface 30 of base 26 of the contactportion 20 of the terminal.

FIG. 5 shows the terminal 10 after it is stamped and formed. The carrierstrip 18 which is manufactured with the terminal 10 is shown in phantom.The carrier strip is used to conveniently gang load the terminal on towall 12 of frame 14. This carrier is severed from the terminal at cut 19after the terminal is fully mounted to frame 14 with legs 28 bent aroundwall 12. FIG. 6 shows the frame 14 without any terminals mounted to it.FIG. 7 is a more complete view of frame 14 showing terminals 10 mountedthereon and the carrier strip already severed. An electrical device suchas a battery (not shown) is held within this frame. Also shown on frame14 are locking ledges 15 upon which a cover (not shown) may snap.

FIGS. 8-10 show an anvil 38 and a punch 40 of a type for crimpingterminating end 22 of one of the terminals 10. Anvil 38 includes atrough 42 into which web 32 of the terminal is positioned. Punch 40includes a dual-radius forming surface 44 for engaging and crimpingsidewalls 34 of the terminal toward each other.

FIG. 9 shows one of the terminals 10 mounted such that terminatingportion 22 is located between anvil 38 and punch 40, with the web 32resting on the anvil and sidewalls 34 projecting upwardly toward thepunch. The contact portion 20 of the terminal would be positioned in anappropriate jig (not shown). In fact, the entire frame 14 (FIG. 1) canbe placed into a jig after the terminals are mounted thereon, and theterminals can be crimped onto their respective flat conductor cables 16simultaneously in a two-position press.

FIG. 10 shows an end view of the terminal positioned between anvil 38and punch 40 with sidewalls 34 projecting upwardly toward the punch. Asthe punch is moved downwardly toward the anvil in the direction of arrow"B", curved forming surfaces 44 engage tips 34b of the sidewalls andbend or form the tips inwardly in the direction of arrows "C".Eventually, sidewalls 34 will be crimped or formed as shown in phantomin FIG. 10, with tips 34b of the sidewalls curved completely under andinto engagement with flat conductor cable 16.

During the crimping operation, tips 34b of sidewalls 34 will be crimpedor bent inwardly toward each other and bypass each other until the tipsreach their eventual terminating positions against the flat conductorcable as shown in FIG. 10. If the tips were not offset longitudinally ofthe terminal as is contemplated by the present invention, theterminating end 22 of the terminal, including web 32, would have to bemade considerably wider as can be understood from the depiction of FIG.10, in order for the tips of the sidewalls to move in an arcuate pathinto their eventual curved and crimped terminating positions.

It will be understood that the invention may be embodied in otherspecific forms without departing from the spirit or centralcharacteristics thereof. The present examples and embodiments,therefore, are to be considered in all respects as illustrative and notrestrictive, and the invention is not to be limited to the details givenherein.

We claim:
 1. An electrical terminal adapted for use with a flatconductor cable, the terminal having a terminating portion and a contactportion of the terminal at one end of the terminating portion, theterminating portion with a generally U-shaped cross-section comprising aweb and a pair of sidewalls extending from two opposite longitudinaledges of the web, the sidewalls being generally triangularly shaped withrelatively wide bases and relatively narrow tips, the bases beingtransversely aligned across the web, and the tips being offset acrossthe web so as to be spaced longitudinally of the web, whereby the tipswill bypass each other when crimped toward each other to terminate theflat conductor cable, the contact portion being generally channel-shapedin cross-section generally transverse to the terminating portioncomprising a generally flat contact surface with legs extending from thecontact surface adapted to be fixed to a dielectric material.
 2. Theelectrical terminal of claim 1 wherein the terminal is stamped andformed of sheet metal material.
 3. The electrical terminal of claim 2wherein the legs extending from the contact surface are bent aroundedges of the dielectric material.
 4. A crimpable electrical terminal forterminating an electrical conductor, comprising:a contact portion at oneend of the terminal; a terminating portion at an opposite end of theterminal; the contact portion and the terminating portion forming anelongated unitary structure of stamped and formed sheet metal material;the terminating portion being generally U-shaped in cross-section andincluding a web and a pair of sidewalls extending from two oppositelongitudinal edges of the web; the sidewalls being generallytriangularly shaped with relatively wide bases, joined to thelongitudinal edges of the web, and relatively narrow tips; the basesbeing offset across the web such that the tips are spaced longitudinallyof the web; the tips being offset across the web such that the tips arespaced longitudinally of the web; whereby the tips will bypass eachother when crimped toward each other to terminate the electricalconductor; and the contact portion being generally channel-shaped incross-section generally transverse to the terminating portion andincluding a generally flat contact surface with legs extending from thecontact surface adapted to be fixed to a dielectric material.
 5. Thecrimpable electrical terminal of claim 4 wherein the legs extending fromthe contact surface are bent around edges of the dielectric material.